California researchers successfully erased and then restored certain memories in rats, a new study declares, offering a potential path for treating Alzheimer’s, post-traumatic stress disorder and other brain ailments.

“It’s very tiny, a fluorescent light that’s shined in, directed precisely at the target that they want it to be aimed at,” says neurologist Chiiko Asanuma, a project officer at the National Institute of Mental Health, which helped fund the study.